1. Field of the Invention
The present invention relates in general to a novel rotational angle sensor which converts rotational angles to corresponding electrical signals.
2. Description of the Prior Art
One prior art rotational angle sensor of the type disclosed herein is arranged to include at least one movable body capable of angular displacement on a rotary axis and a potentiometer having a slider linked to the movable body. In this sensor arrangement, the potentiometer provides an analog voltage output according to the amount of angular displacement of the movable body. In this type of sensor, the potentiometer should desirably have a thin-film resistor which has high wear resistance, and should also provide a stable voltage level output in response to the positions to be assumed by the slider. It is further desirable that the linkage connecting the movable body with the slider should be capable of being operated with reliable stability without causing loose connections. An additional requirement of the sensor is that the contact between the slider and the thin-film resistor should desirably take place with sufficient stability to permit the two contacting parts to resist any vibrations and shocks.
In the prior art sensor, however, the contact between the slider and the thin-film resistor in the potentiometer is implemented by pressure, such that as any one or both of the two contacting elements wear with time and when vibrations or shocks occur, the potentiometer eventually provides incorrect or improper output voltages is response to changes in the angular position of the movable body.